On Fri, Sep 02, 2022 at 08:43:49AM +0000, Christophe Leroy wrote:

Le 01/09/2022 à 21:47, Segher Boessenkool a écrit :

quoted

On Thu, Sep 01, 2022 at 05:41:33AM +0000, Christophe Leroy wrote:

quoted

I think it would be worth a GCC bug report.

We need a stand-alone testcase for this.  When you have created one, at
least 98% of the time you discover the bug is in user code after all.

Which is a very good thing, it means the problem can be fixed simpler,
cheaper, and a lot faster :-)

Easy to reproduce with a .c file that has a single line:

non_existing_macro(xxx);

That was fast (and cheap and simple) :-)

Apparently that's due to the -w option in arch/powerpc/math_emu/Makefile:

	ccflags-y = -w

Was introduced by commit d2b194ed8208 ("powerpc/math-emu: Use kernel 
generic math-emu code")

If I understand correctly it means 'ignore all warnings'. Then it seems 
CLANG doesn't honor that request.

'-w'
     Inhibit all warning messages.

GCC's initial commit has this already (1992).


Segher